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United States Patent | 5,061,472 |
Lailach ,   et al. | October 29, 1991 |
A process for the recovery of sulphuric acid from waste acids containing metal sulphates by evaporative concentration and separation of the metal sulphates from the suspension obtained by evaporation, the improvement wherein vapors leaving the evaporators together with droplets of sulphuric acid containing metal sulphates and solid metal sulphates are condensed by direct contact with cooled contaminated vapor condensate, cooling of this vapor condensate which is circulated as cooling medium is carried out in a flash evaporator and the vapors leaving the flash evaporator free from metal sulphates and sulphuric acid are directly or indirectly condensed by means of cooling agent.
Inventors: | Lailach; Gunter (Krefeld, DE); Gerken; Rudolf (Krefeld, DE) |
Assignee: | Bayer Aktiengesellschaft (Leverkusen, DE) |
Appl. No.: | 562094 |
Filed: | August 1, 1990 |
Aug 23, 1989[DE] | 3927751 |
Current U.S. Class: | 423/531; 159/47.1; 423/522; 423/DIG.2 |
Intern'l Class: | C01B 017/90; B01D 001/00 |
Field of Search: | 423/526,531,529,530,525,527,528,522 |
3948624 | Apr., 1976 | Fornoff et al. | 423/522. |
4157381 | Jun., 1979 | Bodenbenner et al. | 423/531. |
4194952 | Mar., 1980 | Bodenbenner et al. | 423/527. |
Foreign Patent Documents | |||
133505 | Feb., 1985 | EP. | |
194544 | Mar., 1986 | EP | 423/526. |
972412 | Jul., 1959 | DE. | |
940656 | Aug., 1959 | GB. |